Alloy



Patented July 26, 1932 UNITED STATES PATENT OFFICE RICHARD A. WILKINS, OF ROME, NEW YORK, ASS IGNOR 'IO REVERE COPPER AND BRASS INCORPORATED, OF ROME, NEW YORK, A- CORPORATION OF MARYLAND ALLOY No Drawing.

My invention, which relates to alloys, has among its objects the provision of non-ferrous alloy, having both increased tensile strength and elongation as compared to prior alloys, which may be readily and economically attenuated by common mill processes of dra'wf ing and rolling.

The alloy, according to the present invention, is essentially a copper alloy containing other metals, preferably silicon, tin and zinc,

to impart the desired properties. As a typical alloy according to the invention, the same may consist by weight of about 90% copper, 3.25% silicon, 0.5% tin, with the balance zinc. Applicant has found that, generally speaking, if a metal is added to a non-ferrous alloy which acts to increase the tensile strength of the alloy, the elongation or ductility is correspondingly decreased. For example, if'sili- 2 con is added to brass the tensile strength will be increased but the elongation materially decreased. He has further found that silicon, when alloyed with brass, commonly acts to cause the resultant alloy to have a polyphase structure. He has also found that tin has the same effect generally when alloyed with brass, particularly in respect to increasing the tensile strength at the expense of ductility. Applicant has found, however, that by 80 keeping the copper content high as compared to the zinc, and by adding both silicon and tin within definite ranges of these metals, an alloy can be produced in which both the tensile strength and elongation are increased, while at the same time securing a single phase alpha alloy free from segregates. For example, applicant has found that an alloy consisting of 90% copper and 10% zinc when cold rolled and given a slight anneal, will have a tensile strength of about 35,000 pounds per square inch with an elongation of about in two inches, and that the same alloy with 3.25% silicon substituted for part of the zinc, and given the same treatment, will have a tensile strength of about 69,500 pounds per square inch with an elongation of 56% in two inches, but that the same alloy with 3.25% silicon and 0.5% tin substituted for part of the zinc, when given the same treatment, has a tensile strength of about 75,750

Application filed March 24, 1932. Serial No. 601,055;

pounds per square inch with an elongation of about 62.5% in two inches, and at the same time this last mentioned alloy has a single phase alpha structure free from segregates. In other words, the addition of both the sili- 'con and tin secure in respect to elongation a result which neither used alone would secure, and at the same time the tensile strength is increased and the alloy given an improved structure facilitating its workability.

Applicant has further found that besides obtaining the above mentioned simultaneous increase in both tensional strength and elongation'with the production of a workable alloy which has a single phase structure, he may, by use of silicon and tin within definite ranges in proportion of the copper and zinc, secure an increase in the corrosion resisting properties of the alloy that cannot be secured by either the silicon or tin when used alone. For example, the brass having 90% copper, 10% zinc mentioned above is extremely susceptible to the action of boiling acetic acid and boiling dilute sulphuric acid. If the alloy containing 3.25% silicon and no tin and the alloy containing 3.25% silicon and 0.5% tin, both mentioned above, are tested with boiling 10% acetic acid both will show a pronouncedly greater corrosion resistance than the 90% copper, 10% zinc alloy, but the alloy containing both the silicon and tin will show about one-third greater resistance to corrosion than the alloy which contains only the silicon. Then these two alloys are tested with boiling 10% sulphuric acid, the alloy which contains both the silicon and tin shows sults being secured with silicon and tin each as low as 0.25%.

The alloy can be fabricated according to common foundry practice by adding the silicon in the form of a copper alloy rich in this metal to molten brass, after which the tin 2 Laeaere may be added either as metallic tin or as a copper alloy rich in tin, and finally the zinc may be added in the form of brass, and the m lt poured -rie alloy may he rolled or drawn hot or cold and extruded hot by usual mill processes to fabricate sheets, rods, wires, tubes, and the like hav'zsg strong corrosion resistant p;- GTlZlCS. The absence 01" se r ates permitt e rolling and drawing or th s iapes and subsequent machining operations with minimum Wear on the tools employed.

If desired, small percentages of materials other than those above mentioned may be inoorporated into the alloy for imparting desired or special characteristics Without altering the characteristic properties above ment'ioned.

I claim:

1. Alloys containing copper, silicon, tin, and zinc, in which the copper range is from to 95%, the silicon range from 0.25 to et%, the tin range from 0.25 to 1%, nd the bal" ance substantially all zinc, the latter in each particular instance being at least 1%.

2. Substantially sin le phase alloys characterized by a high tensile strength and. elongation containing copper, silicon, tin, and zinc, in which the copper range is from W 85 to 95%, the silicon range from 0.25 to 4%,

the tin range from 0.25 to 1%, and the balance substantially all zinc, the latter in each particular instance being at least 1%.

3. Alloys containing copper, silicon, and in, with the balance substantially all zinc,

in which the copper range is from 85 to 95%,

and the s;licon range is from 0.25 to 4%; in

each particular instance the zinc being at least 1% and the tin being in amount between 325 and 1% suiiicient to increase the tensile strength, the elongation, and the resistance to corrosion as compared to a copper silicon, zinc alloy having the same percentage amounts of copper and silicon.

' 4. An alloy containing approximately copper, 3.25% silicon, 0.5% tin with the balance zinc.

In testimony whereof, l have signed my name to this specification.

m RICHARD A. VVILKINS. 

